Are there math journals that are aimed for undergraduates? I don't mean here journals where students can publish their papers, but journals that publish introductory articles that an undergraduate can read without too much sweating, preferably when he gets bored or tired from his assignments and wants to read something different. What journals do you recommend to undergrads to read on a regular basis?

The journal "Morfismos" published by CINVESTAV, Mexico, is aimed at undergraduate and graduate students. Although some articles are in Spanish, they publish fairly good expository articles in English. For example, there is a survey on the recent solution of the Kervaire invariant one problem in this issue.

From their home page: ``Plus provides articles and podcasts on any aspect of mathematics, covering topics as diverse as art, medicine, cosmology and sport, a news section, showing how recent news stories were often based on some underlying piece of maths that never made it to the newspapers, reviews of popular maths books, and puzzles for you to sharpen your wits. We have a regular interview with someone in a maths-related career, showing the wide range of uses maths gets put to in the real world."

The intended audience is not limited to math undergraduates; science undergrads would find something interesting there, too. Some articles can be accessible even to high-school students.

And for those who read Polish, there is ``Delta" (which I used to read regularly in the paper version as an undergrad):

If you understand french, "Quadrature" is also a good magazine which for instance contains sections about counter examples and history of mathematics. Recently a special issue about Poincaré has been published.